JP2019174693A - Display system, control unit, control method, program, and movable body - Google Patents

Abstract

To prevent a reduction in display quality and visibility of a virtual image.SOLUTION: An display system 1 comprises an image forming unit 2 and a projection unit 3. The image forming unit 2 has a display surface 210 and forms an image on the display surface 210. The projection unit 3 projects, in a target space, a virtual image 300 corresponding to the image with output light from the image forming unit 2. The display system 1 can change the viewing distance L0 from an eye box 800 to the virtual image 300. The display system 1 further includes an adjustment unit 50 that adjusts the brightness of the virtual image 300 according to the viewing distance L0.SELECTED DRAWING: Figure 1

Description

  The present invention generally relates to a display system, a control device, a control method, a program, and a moving object. More specifically, the present invention relates to a display system that projects a virtual image, a control device that includes an adjustment unit used in the display system, a control method and program for the display system, and a moving body that includes the display system. .

  As a conventional example, a vehicle display device described in Patent Document 1 is illustrated. This vehicular display device projects a display image on windproof glass in which a combiner is incorporated. The vehicular display device includes light emitting display means that is installed below the windshield glass and includes a light source unit, a lens that is a collimator, and a transmissive display body. In the vehicular display device, the light emitting display means (for example, a lens) is moved back and forth in the direction of the light emitted toward the combiner in accordance with the vehicle speed to change the imaging position of the virtual image to be displayed. As a result, the viewing distance from the virtual image observer (eye box) to the virtual image can be changed.

Japanese Utility Model Publication No. 6-87043

  By the way, when the luminance of the light source unit is constant, if the lens is simply moved back and forth as in the vehicle display device of Patent Document 1 in order to change the viewing distance, the luminance of the virtual image is high for an observer who observes the virtual image. There is a possibility of feeling uncomfortable as if it fluctuated. For this reason, the display quality of the virtual image is lowered, and the visibility of the virtual image may be lowered.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a display system, a control device, a control method, a program, and a moving body capable of suppressing the display quality and visibility of a virtual image.

  A display system according to one embodiment of the present invention includes an image forming unit and a projection unit. The image forming unit has a display surface and forms an image on the display surface. The projection unit projects a virtual image corresponding to the image onto the target space by the output light of the image forming unit. The display system is configured to be able to change the viewing distance from the eye box to the virtual image. The display system further includes an adjustment unit that adjusts the brightness of the virtual image according to the viewing distance.

  The control apparatus which concerns on 1 aspect of this invention is provided with the adjustment part used for the said display system.

  A control method according to one embodiment of the present invention is a control method for a display system. The display system includes an image forming unit and a projection unit. The image forming unit has a display surface and forms an image on the display surface. The projection unit projects a virtual image corresponding to the image onto the target space by the output light of the image forming unit. The display system is configured to be able to change the viewing distance from the eye box to the virtual image. The control method includes an adjustment process for adjusting the brightness of the virtual image according to the viewing distance.

  A program according to an aspect of the present invention causes a computer system to execute the display system control method.

  The moving body which concerns on 1 aspect of this invention is provided with the said display system and the reflection member which reflects the light from the said projection part.

  The present invention has an advantage that it is possible to suppress the degradation of display quality and visibility of a virtual image.

FIG. 1 is a schematic block diagram of a display system according to an embodiment. FIG. 2 is a conceptual diagram of a mobile body (automobile) provided with the above display system. FIG. 3 is a conceptual diagram showing the field of view of the user who drives the moving body. FIG. 4A is a diagram illustrating a virtual image when the image size is not adjusted when the viewing distance is changed in the above display system, and FIG. 4B is a case where the image size is adjusted when the viewing distance is changed. It is a figure which shows the mode of the image in. FIG. 5 is a flowchart for explaining the operation of the adjustment unit in the above display system. FIG. 6 is a schematic block diagram of Modification 3 of the above display system. FIG. 7 is a schematic block diagram of a display system including a control device according to an embodiment.

(1) Outline The following embodiment is only one of various embodiments of the present invention. The following embodiments can be variously modified according to the design or the like as long as the object of the present invention can be achieved. Moreover, FIGS. 1-7 demonstrated in the following embodiment are typical figures, The ratio of the magnitude | size of each component in FIGS. 1-7 reflects the actual dimensional ratio necessarily. Not necessarily.

  As shown in FIG. 1, the display system 1 of this embodiment includes an image forming unit 2 and a projection unit 3. The image forming unit 2 has a display surface 210 and forms an image 7 (see FIG. 4B) on the display surface 210. The projection unit 3 projects a virtual image 300 corresponding to the image 7 onto the target space 400 by the output light of the image forming unit 2. The “target space” referred to here is assumed to be a space including a region where an image of the display system 1 is formed, for example.

  As shown in FIGS. 1 to 3, the display system 1 is assumed to be a head-up display (HUD) used in the automobile 100 as a moving body. Therefore, the target space 400 is a space outside the passenger compartment of the automobile 100 and is mainly a space in front of the windshield 101 (reflecting member) of the automobile 100.

  However, the display system 1 is not limited to the head-up display used in the automobile 100, and can be applied to a mobile body other than the automobile 100 such as a motorcycle, a train, an aircraft, a construction machine, and a ship. Furthermore, the display system 1 is not limited to a head-up display, but may be applied to an AR (Augmented Reality) display device that superimposes information in the real world.

  Further, as shown in FIG. 1, the display system 1 is configured to be able to change the viewing distance L0 from the eye box 800 to the virtual image 300. The eye box 800 is a spatial region in which the eyes of the observer (user 200) of the virtual image 300 are assumed to exist.

  Here, the display system 1 of the present embodiment further includes an adjustment unit 50 (see FIG. 1) that adjusts the brightness of the virtual image 300 according to the viewing distance L0. Here, as an example, the brightness of the virtual image 300 is adjusted by changing the luminance of the display surface 210. However, the brightness of the virtual image 300 may be adjusted by changing the brightness of the content included in the image 7 (see Modification 1 described later).

  According to this configuration, when the viewing distance L0 is changed, the brightness of the virtual image 300 with respect to the observer (user 200) compared to the case where the lens is simply moved back and forth as in the vehicle display device of Patent Document 1. The possibility of giving a sense of incongruity as if fluctuated can be reduced. As a result, it is possible to suppress the display quality and visibility of the virtual image 300 from being lowered.

(2) Details (2.1) Overall Configuration Hereinafter, the display system 1 of the present embodiment will be described in detail with reference to FIGS. As shown in FIG. 1, the display system 1 includes a display device 4 and is applied to an automobile 100 that is a moving body as an example, as described in the section “(1) Overview” above. The display device 4 is a head-up display used for the automobile 100 as an example.

  Hereinafter, as an example, it is assumed that the adjustment unit 50 described in the column “(1) Overview” is provided in the control unit 5 of the display device 4.

(2.2) Display Device The display device 4 is installed in the vehicle interior of the automobile 100 so that the image 7 (see FIG. 4B) is projected onto the windshield 101 of the automobile 100 from below. In the example of FIG. 2, the display device 4 is disposed in the dashboard 102 below the windshield 101. As shown in FIG. 1, the display device 4 includes an image forming unit 2, a projection unit (optical system) 3, a control unit 5, a drive unit 6, and a detection unit X <b> 1.

  The image forming unit 2 outputs light for forming the image 7. In the present embodiment, as an example, the image forming unit 2 includes a liquid crystal panel 21 (LCD: Liquid Crystal Display) and a light source device 22 as shown in FIG. The liquid crystal panel 21 has a display surface 210 on the front surface, and forms an image 7 on the display surface 210. The liquid crystal panel 21 is disposed in front of the light source device 22. The light source device 22 is used as a backlight of the liquid crystal panel 21. The light source device 22 is a so-called surface light source. The light source device 22 is a sidelight type light source device using a solid light emitting element such as a light emitting diode or a laser diode. Light from the light source device 22 passes through the liquid crystal panel 21 and is output from the image forming unit 2.

  In the image forming unit 2, when the light source device 22 emits light while the image 7 is displayed on the liquid crystal panel 21, the light output forward from the light source device 22 is transmitted through the liquid crystal panel 21 and the liquid crystal panel 21. Output from the front of the panel 21 forward. At this time, the light output forward from the front surface of the liquid crystal panel 21 is light reflecting the image 7 displayed on the liquid crystal panel 21, and as a result, the image forming unit 2 forms light that forms the image 7. Is output as “output light”.

  Here, the vertical direction of the liquid crystal panel 21 is the vertical direction of the projected image 7, and the horizontal direction of the liquid crystal panel 21 is the horizontal direction of the projected image 7. The vertical direction of the projected image 7 is the vertical direction of the virtual image 300 (see FIGS. 1 to 3) projected onto the target space 400, that is, the direction along the vertical direction in the visual field of the user 200 (see FIG. 2). is there. The horizontal direction of the projected image 7 is the horizontal direction of the virtual image 300 projected onto the target space 400, that is, the direction along the horizontal direction in the visual field of the user 200.

  The projection unit 3 projects the image 7 by reflecting the output light of the image forming unit 2. In the present embodiment, the display device 4 is a head-up display as described above, and projects the image 7 onto the windshield 101 (see FIG. 1) that is a reflecting member. Therefore, the projection unit 3 includes the windshield 101. The image 7 is projected onto the object.

  In the present embodiment, as an example, the projection unit 3 includes a mirror 31 and a zoom lens 32 (lens group) as shown in FIG. The zoom lens 32 is disposed between the display surface 210 of the liquid crystal panel 21 and the mirror 31. The zoom lens 32 includes, for example, a drive lens 321 having a light diverging action and a fixed lens 322 having a light collecting action. In the projection unit 3, the fixed lens 322, the drive lens 321, and the mirror 31 are arranged in this order on the optical path of the light output from the display surface 210 of the liquid crystal panel 21. Here, the zoom lens 32 is a lens group including two lenses, but the number of lenses is not particularly limited.

  The projection unit 3 first collects the output light of the image forming unit 2 by the fixed lens 322, diverges it by the drive lens 321, reflects it by the mirror 31, and emits it toward the windshield 101. As an example, the mirror 31 is a concave mirror. The mirror 31 is arranged on the side opposite to the light source device 22 as viewed from the liquid crystal panel 21, that is, in front of the liquid crystal panel 21 so that the output light of the image forming unit 2 is incident.

  With the configuration as described above, the projection unit 3 projects the image 7 formed by the image forming unit 2 to an appropriate size and projects it as a projection image onto the windshield 101, which is the target object. A virtual image 300 is projected onto 400. The “virtual image” referred to here means an image that is concatenated so that an object is actually present by the diverging light beam when the light emitted from the display device 4 diverges by a reflector such as the windshield 101.

  In the display device 4, the virtual image 300 formed in the target space 400 is formed on a virtual plane 501 that intersects the optical axis 500 of the display device 4 as illustrated in FIG. 2. In the present embodiment, the optical axis 500 is along the road surface 600 in front of the automobile 100 in the target space 400 in front of the automobile 100. A virtual surface 501 on which the virtual image 300 is formed is substantially perpendicular to the road surface 600. For example, when the road surface 600 is a horizontal plane, the virtual image 300 is displayed along the vertical plane.

  Therefore, as shown in FIG. 3, the user 200 driving the automobile 100 can see the virtual image 300 projected on the display device 4 so as to overlap the real space spreading in front of the automobile 100. Therefore, according to the display device 4, for example, various driving support information such as vehicle speed information, navigation information, pedestrian information, forward vehicle information, lane departure information, and vehicle condition information is displayed as the virtual image 300, and the user 200 can be visually recognized. In the example of FIG. 3, the virtual image 300 includes a first virtual image 300A and a second virtual image 300B. The content of the first virtual image 300A (hereinafter referred to as “content”) includes the direction and position of an arrow. The content of the second virtual image 300B is vehicle speed information, and shows information “50 km / h” as an example. As a result, the user 200 can visually acquire the driving support information by only a slight line-of-sight movement from a state where the line-of-sight is directed in front of the windshield 101.

  The control unit 5 controls the image forming unit 2 (the liquid crystal panel 21 and the light source device 22). The control unit 5 controls the drive unit 6. The control unit 5 is composed of, for example, a microcomputer having a CPU (Central Processing Unit) and a memory as main components. In other words, the control unit 5 is realized by a computer having a CPU and a memory, and the computer functions as the control unit 5 when the CPU executes a program stored in the memory. Here, the program is recorded in advance in the memory of the control unit 5, but may be provided through a telecommunication line such as the Internet or recorded in a recording medium such as a memory card.

  The control unit 5 controls the image forming unit 2 to form an arbitrary image 7 on the display surface 210. That is, the control unit 5 can display (draw) arbitrary video content on the liquid crystal panel 21 by software processing, whereby an arbitrary image 7 is formed on the display surface 210. For example, when the virtual image 300 (the first virtual image 300A and the second virtual image 300B) as shown in FIG. 3 is projected onto the target space 400, the contents of the first virtual image 300A (direction of arrow, position, etc.) and the second virtual image 300B The contents (vehicle speed, etc.) are determined by the control unit 5. Further, the control unit 5 also determines the position of the image 7 on the front surface of the liquid crystal panel 21, that is, the display surface 210. In short, the control unit 5 can display, for example, the image 7 corresponding to the first virtual image 300 </ b> A on the upper half of the display surface 210 or the lower half of the display surface 210. If the position of the image 7 on the display surface 210 changes, the relative display position of the virtual image 300 also changes.

  By the way, the display system 1 of this embodiment is comprised so that the visual distance L0 from the eye box 800 to the virtual image 300 can be changed, as shown in FIG. Specifically, the drive unit 6 moves the optical element included in the projection unit 3 to change the viewing distance L0. That is, the drive unit 6 changes the position of the optical element. In the present embodiment, the drive target of the drive unit 6 is a drive lens 321 as an example. The drive unit 6 increases or decreases the viewing distance L0 from the eye box 800 to the virtual image 300 by moving the drive lens 321 in a direction toward or away from the fixed lens 322 under the control of the control unit 5. It can be changed. The drive unit 6 is composed of, for example, an electrically driven actuator such as a motor. Although a detailed description is omitted, the drive unit 6 may be configured to physically change the position or orientation of the display surface 210 of the liquid crystal panel 21, or the mirror 31 may be rotated to rotate the mirror 31. It may be configured to change the orientation.

  Here, when the distance between the drive lens 321 and the image forming unit 2 is moved in the direction of reducing the viewing distance L0, the viewing distance L0 increases. This is because the magnification of the zoom lens 32 is increased by reducing the interval. However, if the interval is simply reduced at this time, the display angle of view (viewing angle) when the virtual image 300 is viewed from the user 200 is increased as shown in FIG. 4A. 4A schematically shows a virtual image 300 that can be seen by the user 200 as a grid-like rectangle. Reference numeral 301 represents the virtual image 300 before the change in the viewing distance L0, and reference numeral 303 represents the virtual image 300 after the change in the viewing distance L0. Represents. That is, if the size of the image 7 displayed on the image forming unit 2 remains constant before and after the drive lens 321 moves, the size of the virtual image 300 viewed by the user 200 changes. . In the example of FIG. 4A, the size of the virtual image 300 is increased.

  Therefore, the control unit 5 displays the image on the image forming unit 2 in accordance with the movement of the driving lens 321 in order to make the display angle of view constant before and after the movement of the driving lens 321 for increasing the viewing distance L0. The size of the image 7 to be performed is reduced (see FIG. 4B). FIG. 4B schematically shows the image 7 formed on the display surface 210 of the image forming unit 2 as a grid-like rectangle, the reference numeral 70 represents the image 7 before the size change, and the reference numeral 71 represents the size after the size change. Represents the (reduced) image 7. The control unit 5 determines the driving amount of the driving unit 6 and the size of the image 7. At this time, the drive amount of the drive unit 6 and the change amount of the size of the image 7 formed on the display surface 210 are proportional, for example. Thus, by making the display field angle constant before and after the movement of the drive lens 321, for example, the display field angle of the virtual image 300 increases with an increase in the viewing distance L 0, and the user 200 viewing the virtual image 300 can be viewed. Giving a sense of incongruity can be suppressed. However, the phrase “make the display angle of view constant” does not have to be strictly “constant”, and the display angle of view may be substantially constant within a predetermined range including some allowable error. .

  The size of the image 7 displayed on the display surface 210 of the image forming unit 2 is the size of the image displayed using the pixels used for displaying the content among the pixels constituting the display surface 210. .

  And the control part 5 of this embodiment is provided with the adjustment part 50 which adjusts the brightness of the virtual image 300 according to the change of the visual distance L0 by the drive part 6, as shown in FIG. The adjustment unit 50 will be described in detail in the next section “(2.3) Adjustment unit”.

  The detection unit X1 detects ambient illuminance, for example, illuminance in the target space 400 outside the passenger compartment, including a region where the image of the display device 4 is formed, and sends the detected illuminance to the control unit 5. It is configured.

  As shown in FIG. 1, the detection unit X1 includes an illuminance sensor X10, an amplification unit X11, an A / D conversion unit X12, and the like. The illuminance sensor X10 is configured by, for example, a photo IC (Integrated Circuit) that detects the illuminance of the target space 400, and is disposed near the opening 103 in the dashboard 102 of the automobile 100. The illuminance sensor X10 outputs an illuminance voltage (analog signal) corresponding to the illuminance of the target space 400 to the amplification unit X11. The amplification unit X11 amplifies the signal input from the illuminance sensor X10 and outputs the amplified signal to the A / D conversion unit X12. The A / D conversion unit X12 converts the output signal of the amplification unit X11 into a digital signal and sends it to the control unit 5 as an illuminance value (detection value).

(2.3) Adjustment Unit Hereinafter, the configuration centering on the adjustment unit 50 of the control unit 5 will be described in detail. Note that the description of the basic control processing relating to the video content rendering of the image forming unit 2 and the driving of the driving unit 6 described above may be omitted as appropriate.

  As shown in FIG. 1, the control unit 5 includes an adjustment unit 50, an input unit 51, an output unit 52, and a storage unit 53. Note that the storage unit 53 may be the memory described above, or may be provided separately from the memory.

  The control unit 5 receives an operation input from the user 200 through an operation unit (not shown), or performs control to change the viewing distance L0 through the drive unit 6 in automatic control according to video content to be displayed. And the adjustment part 50 is comprised so that the brightness of the virtual image 300 may be adjusted (adjustment process) according to the change of the visual distance L0. Here, the adjustment unit 50 increases the brightness of the virtual image 300 as the viewing distance L0 increases. The adjustment unit 50 adjusts the brightness of the virtual image 300 by changing the luminance of the display surface 210. In short, the control unit 5 changes both the size of the image 7 displayed on the liquid crystal panel 21 and the amount of light output from the liquid crystal panel 21 according to the driving amount of the driving unit 6.

  The storage unit 53 is a rewritable memory and is preferably a non-volatile memory. The storage unit 53 includes, for example, first data in which the driving amount is associated with the size of the image 7, and second data in which the driving amount is associated with the light amount (target value) of the backlight (light source device 22). Pre-stored. As described above, the first data is preferably data in which the drive amount and the amount of change in the size of the image 7 are proportional. The second data is preferably obtained by analyzing the light quantity distribution of the light source device 22 in advance by a test or the like. In particular, the light intensity (candela) emitted from the light source device 22 to the display surface 210 is not completely uniform over the entire area of the display surface 210 and varies to some extent. For example, the brightness of the central region of the display surface 210 is stronger. Therefore, the brightness of the projected virtual image 300 also changes depending on the display position of the image 7 on the display surface 210 (for example, whether it is displayed in the central region of the display surface 210, or displayed above or below the central region). come. Therefore, the light amount distribution of the light source device 22 with respect to the area of the display surface 210 is one of important parameters in the adjustment process of the adjustment unit 50 performed in accordance with the change in the viewing distance L0. As a result, it is preferable that the second data includes a plurality of light amounts (target values) respectively corresponding to the display positions (XY coordinates) of the image 7 on the display surface 210.

  In particular, as described above, the control unit 5 moves the drive lens 321 in order to make the display angle of view constant before and after the movement of the drive lens 321 for increasing (or decreasing) the viewing distance L0. Accordingly, the size of the image 7 displayed on the image forming unit 2 is changed. However, when the size of the image 7 is reduced, for example, the use range used for displaying the image 7 on the display surface 210 is narrowed. As a result, if the adjustment unit 50 is not provided and the light amount of the light source device 22 does not change, the brightness of the virtual image 300 that can be seen by the user 200 decreases.

  On the other hand, the adjusting unit 50 is based on the second data so that the brightness of the virtual image 300 is substantially constant even when the viewing distance L0 is changed, that is, the brightness of the virtual image 300 is within a predetermined target range. Generate a control signal. The control unit 5 outputs a control signal to the image forming unit 2 to adjust the brightness of the virtual image 300. Therefore, even if the size of the image 7 is changed in order to keep the display angle of view of the virtual image 300 constant, it can be suppressed that the brightness of the virtual image 300 seen by the user 200 changes and the virtual image 300 looks dim and blurry. Therefore, it is possible to suppress the display quality and visibility of the virtual image 300 from being lowered.

  Note that the adjustment unit 50 increases the power of the light source device 22 so as to increase exponentially so as to draw a curve from the current light amount to the light amount of the target value determined based on the second data, rather than increasing proportionally. It is preferable to control the amount of light.

  Regardless of whether or not the viewing distance L0 is changed, the adjustment unit 50 periodically receives the detection value from the detection unit X1, and adjusts the luminance of the virtual image 300 according to the detection value. For example, if the ambient illuminance changes due to daytime and nighttime or when the automobile 100 enters the tunnel, the visibility of the virtual image 300 may be reduced. Therefore, the storage unit 53 stores in advance data in which the detection value is associated with the light amount (target value) of the light source device 22. In order to prevent a reduction in visibility, the adjustment unit 50 controls the light source device 22 so as to substantially match the target light amount corresponding to the detection value received from the detection unit X1, based on the data in the storage unit 53. The brightness of the virtual image 300 is adjusted. In addition to the automatic brightness adjustment, the adjustment unit 50 receives a predetermined operation input from the user 200 through an operation unit (not shown), thereby controlling the light source device 22 and adjusting the brightness of the virtual image 300.

  The input unit 51 is electrically connected to the output terminal of the A / D conversion unit X12 of the detection unit X1 via the signal line S11 (see FIG. 1). The input unit 51 is configured to periodically receive a detection value of illuminance from the detection unit X1.

  The output unit 52 is electrically connected to the image forming unit 2 via a signal line S12 (see FIG. 1). The output unit 52 is configured to output the control signal generated by the adjustment unit 50 to the image forming unit 2. When the image forming unit 2 receives the control signal, the image forming unit 2 causes the lighting circuit that performs lighting control of the light source in the light source device 22 to change the light output of the light source so that the light amount corresponds to the control signal.

  Here, the adjustment unit 50 preferably adjusts the brightness of the virtual image 300 in consideration of the detection value received from the detection unit X1 when the viewing distance L0 is changed. For example, the second data may include a plurality of types of data tables respectively corresponding to daytime use, nighttime use, and tunnel use. If the adjustment unit 50 determines that the current time zone is, for example, nighttime from the acquired detection value, the adjustment unit 50 selects a nighttime data table, and based on the data table, the light source corresponding to the driving amount of the driving unit 6 The light amount (target value) of the device 22 may be determined.

  The control unit 5 is electrically connected to an ECU (Electronic Control Unit) mounted on the automobile 100, and is configured to transmit and receive various electric signals with the ECU.

(2.4) Operation of Adjustment Unit The operation of the adjustment unit 50 will be described below with reference to the flowchart of FIG. Here, as an example, as shown in FIG. 1, description will be made assuming that the viewing distance L0 is increased from the first distance L1 to the second distance L2.

  First, when the control unit 5 determines to change the viewing distance L0, the control unit 5 determines the drive amount of the drive unit 6 (here, the displacement amount of the drive lens 321) corresponding to the difference between the first distance L1 and the second distance L2. (Step S1). When the drive amount is determined, the control unit 5 refers to the first data in the storage unit 53 and determines the reduced size of the image 7 corresponding to the drive amount (step S2). Moreover, the control part 5 starts execution of the adjustment process by the adjustment part 50 (step S3).

  The adjustment unit 50 refers to the second data in the storage unit 53 and selects a data table that matches the current illuminance using the latest detection value received from the detection unit X1 (step S4). The adjustment unit 50 determines the driving amount and the light amount (target value) of the light source device 22 corresponding to the display position of the image 7 on the display surface 210 based on the selected data table (step S5).

  When the displacement amount of the driving lens 321, the size of the image 7, and the target value of the light amount are determined, the control unit 5 sends a control signal including such information to the driving unit 6 and the image forming unit 2 (step S <b> 6). . Specifically, the control unit 5 controls the driving unit 6 to move the driving lens 321 so as to approach the fixed amount of displacement with respect to the fixed lens 322 (see the arrow in FIG. 1). Further, the control unit 5 causes the image forming unit 2 to reduce the size of the image 7 simultaneously with the control of the driving unit 6. Further, the control unit 5 causes the image forming unit 2 to gradually increase the current light amount of the light source device 22 to the light amount of the target value.

  As a result, the virtual image 300 (301) located at the first distance L1 from the eye box 800 moves further away from the eye box 800 and moves from the eye box 800 to the second distance L2 (the virtual image 300 (FIG. 1)). 302)). And in this embodiment, even if the visual distance L0 of the virtual image 300 is changed, the adjustment process of the adjustment part 50 can aim at suppression of the display quality of the virtual image 300, and the fall of visibility.

(3) Modified Examples Below, several modified examples are listed. Hereinafter, the above-described embodiment is referred to as a “basic example”. Each of the modified examples described below can be applied in appropriate combination with the basic example and other modified examples described above.

(3.1) Modification 1
In the basic example, the adjustment unit 50 adjusts the brightness of the virtual image 300 by changing the luminance of the display surface 210. However, the adjustment unit 50 may be configured to adjust the brightness of the virtual image 300 by changing the brightness (color brightness) of the content included in the image 7. Of course, the adjustment unit 50 may be configured to adjust the brightness of the virtual image 300 by appropriately changing both the luminance of the display surface 210 and the brightness of the content. The liquid crystal panel 21 may be an LCD capable of full color display, for example.

  Specifically, the adjustment unit 50 changes the brightness according to the content included in the image 7. For example, in FIG. 3, for the second virtual image 300B including the content of vehicle speed information, the visual distance L0 of only the first virtual image 300A including the content of the direction of the arrow may be changed without changing the visual distance L0. Suppose that when the viewing distance L0 is the first distance L1, the display color of the second virtual image 300B is a light gray color close to white. The adjustment unit 50 may lower the brightness of the second virtual image 300B so that the amount of black gradually increases when the viewing distance L0 is changed to the second distance L2. By reducing the brightness when the viewing distance L0 increases, it is possible to suppress the first virtual image 300A from being dimly blurred.

  The lightness target value may be determined by the display color alone of the first virtual image 300A, but is correlated with the display color of the second virtual image 300B that is displayed near the first virtual image 300A and does not change the viewing distance L0. May be determined by:

  Alternatively, the adjustment unit 50 may change the content of the virtual image 300 when changing the viewing distance L0. For example, when the viewing distance L0 is the first distance L1, the virtual image 300 including both the vehicle speed information and the navigation information contents is displayed, and when changing to the second distance L2, the navigation information contents are erased and only the vehicle speed information contents are displayed. You may display the virtual image 300 containing. In this case, the adjustment unit 50 may change the brightness according to the change of the content.

(3.2) Modification 2
In the basic example, when changing the viewing distance L0, the control unit 5 changes the size of the image 7 so that the display angle of view of the virtual image 300 is constant before and after the drive lens 321 moves. . However, the display angle of view of the virtual image 300 may not be constant before and after the movement of the drive lens 321.

  For example, when the viewing distance L0 is increased, the adjustment unit 50 may change the size of the image 7 so that the display angle of view of the virtual image 300 is decreased. Further, whether or not the display angle of view of the virtual image 300 is made constant may be appropriately changed according to the content included in the image 7.

(3.3) Modification 3
In the basic example, the image forming unit 2 includes a liquid crystal panel 21 (LCD: Liquid Crystal Display) with a backlight, but is not limited to an LCD. As shown in FIG. 6, the display device 4 includes an image forming unit 2 </ b> A having a diffusion transmission type screen 23 and an irradiation unit 24 that irradiates the screen 23 with light from behind the screen 23. (Modification 3).

  The irradiation unit 24 is a scanning light irradiation unit, and irradiates the screen 23 with light. Thereby, the image 7 (see FIG. 4B) is drawn by the light from the irradiation unit 24 on the display surface 230 which is the front surface or the back surface (here, the front surface) of the screen 23, and the target space is transmitted by the light transmitted through the screen 23. A virtual image 300 is formed at 400.

  The irradiation unit 24 includes a light source 241 that outputs laser light, a scanning unit 242 that scans light from the light source 241, and a lens 243. The light source 241 includes a laser module that outputs laser light. The scanning unit 242 irradiates the screen 23 with light for scanning the display surface 230 by scanning light from the light source 241. Here, the scanning unit 242 performs a raster scan that scans light two-dimensionally in the vertical and horizontal directions of the display surface 230. In other words, the scanning unit 242 forms a two-dimensional image by scanning the bright spots formed on the display surface 230. The scanning unit 242 includes a minute scanning mirror using, for example, a MEMS (Micro Electro Mechanical Systems) technique. That is, the scanning unit 242 includes an optical element (mirror unit) that reflects the laser light, and rotates the optical element so that the light from the light source 241 is directed according to the rotation angle (deflection angle) of the optical element. reflect. Thereby, the scanning unit 242 scans the light from the light source 241. The scanning unit 242 realizes a raster scan that scans light two-dimensionally by rotating the optical element about two axes orthogonal to each other.

  Note that the display device 4 of the present modification includes a projection unit 3 </ b> A having a first mirror 33 and a second mirror 34. The first mirror 33 and the second mirror 34 are arranged in the order of the first mirror 33 and the second mirror 34 on the optical path of the light output from the image forming unit 2A. The first mirror 33 reflects the output light of the image forming unit 2 </ b> A toward the second mirror 34. The second mirror 34 reflects the output light of the image forming unit 2 </ b> A reflected by the first mirror 33 toward the windshield 101. The first mirror 33 is a convex mirror, and the second mirror 34 is a concave mirror.

  In the present modification, the drive target of the drive unit 6 is the screen 23. The control unit 5 drives the screen 23 by controlling the drive unit 6 in order to change the viewing distance L0. The drive unit 6 increases or decreases the viewing distance L0 from the eye box 800 to the virtual image 300 by moving the screen 23 in a direction approaching or moving away from the lens 243 under the control of the control unit 5. It can be changed.

  The adjustment unit 50 of the control unit 5 is configured to adjust the brightness of the virtual image 300 (adjustment process) in accordance with the change in the viewing distance L0. The control unit 5 changes both the size of the image 7 displayed on the screen 23 and the amount of light output from the light source 241 according to the drive amount of the drive unit 6.

  Also in this modified example, it is possible to suppress a decrease in display quality and visibility of the virtual image 300 that may occur due to a change in the viewing distance L0.

(3.4) Modification 4
In the basic example, the adjustment unit 50 is provided in the control unit 5 of the display device 4. However, the adjustment unit 50 may be provided separately from the display device 4. For example, as illustrated in FIG. 7, the control device 10 including the adjustment unit 50 may be provided separately from the display device 4.

  The display system 1 includes a display device 4 and a control device 10. The display device 4 includes an image forming unit 2, a projecting unit 3, a driving unit 6, a control unit 5 (having a control function other than the adjustment unit 50), a detection unit X 1, and a signal of the control device 10. A communication interface capable of transmitting and receiving). When receiving the control signal for adjusting the brightness of the virtual image 300 from the control device 10, the control unit 5 of the display device 4 controls the image forming unit 2 in accordance with the control signal. In this case, the control device 10 is, for example, an ECU (Electronic Control Unit) mounted in the automobile 100, and the function of the adjustment unit 50 may be provided in the ECU.

(3.5) Other Modifications As the image forming unit 2, for example, an organic light emitting diode (electroluminescence) panel may be used.

  In addition to the driving lens 321 of the basic example and the screen 23 of the third modification, the driving target of the driving unit 6 at the time of changing the viewing distance L0 may be, for example, a mirror or the liquid crystal panel 21.

  Functions similar to those of the control unit 5 (mainly the adjustment unit 50) in the basic example may be realized by a computer program, a non-transitory recording medium that records the program, or the like. Here, the execution subject of the adjustment unit 50 includes a computer system. The computer system mainly includes a processor and a memory as hardware. When the processor executes the program recorded in the memory of the computer system, the function as the execution subject of the adjustment unit 50 is realized. The program may be recorded in advance in the memory of the computer system, but may be provided through an electric communication line, or may be provided by being recorded in a recording medium such as a memory card, an optical disk, or a hard disk drive that can be read by the computer system. May be. A processor of a computer system includes one or more electronic circuits including a semiconductor integrated circuit (IC) or a large scale integrated circuit (LSI). The plurality of electronic circuits may be integrated into one chip, or may be distributed and provided on a plurality of chips. The plurality of chips may be integrated into one device, or may be distributed and provided in a plurality of devices.

  Moreover, although the control part 5 of a basic example is implement | achieved by one apparatus, it is not limited to this structure. For example, at least one function among a plurality of functions in the control unit 5 may be distributed and provided in two or more devices. Similarly, at least one of the functions of the illuminance sensor X10, the amplification unit X11, and the A / D conversion unit X12 in the detection unit X1 may be distributed and provided in two or more devices. In addition, at least a part of the functions of the control unit 5 may be realized by, for example, cloud (cloud computing).

(4) Advantages As described above, the display system (1) according to the first aspect includes the image forming unit (2, 2A) and the projection unit (3, 3A). The image forming unit (2, 2A) has display surfaces (210, 230), and forms an image (7) on the display surfaces (210, 230). The projection unit (3, 3A) projects a virtual image (300) corresponding to the image (7) onto the target space (400) by the output light of the image forming unit (2, 2A). The display system (1) is configured to be able to change the viewing distance (L0) from the eye box (800) to the virtual image (300). The display system (1) further includes an adjustment unit (50) that adjusts the brightness of the virtual image (300) according to the viewing distance (L0). According to the first aspect, it is possible to suppress the display quality and visibility of the virtual image (300) from being lowered.

  Regarding the display system (1) according to the second aspect, in the first aspect, it is preferable that the adjustment unit (50) further adjusts the brightness of the virtual image (300) according to the ambient illuminance. According to the 2nd aspect, the display quality and visibility fall of a virtual image (300) can further be suppressed.

  Regarding the display system (1) according to the third aspect, in the first or second aspect, the adjustment unit (50) changes the brightness of the display surface (210, 230) to change the brightness of the virtual image (300). It is preferable to adjust. According to the 3rd aspect, although it is a simple structure, the fall of the display quality and visibility of a virtual image (300) can be suppressed.

  With respect to the display system (1) according to the fourth aspect, in any one of the first to third aspects, the adjustment unit (50) changes the brightness of the content included in the image (7) to change the virtual image ( 300) is preferably adjusted. According to the 4th aspect, although it is a simple structure, the fall of the display quality and visibility of a virtual image (300) can be suppressed.

  Regarding the display system (1) according to the fifth aspect, in any one of the first to fourth aspects, the adjustment unit (50) increases the brightness of the virtual image (300) as the viewing distance (L0) increases. It is preferable to lighten the thickness. According to the fifth aspect, it is possible to suppress deterioration in display quality and visibility of the virtual image (300) accompanying an increase in the viewing distance (L0) (for example, dim and blurred).

  Regarding the display system (1) according to the sixth aspect, in any one of the first to fifth aspects, the display angle of view of the virtual image (300) projected by the projection unit (3, 3A) is the viewing distance. It is preferable that (L0) is constant even if it changes. According to the sixth aspect, it is possible to suppress a situation in which, for example, the display angle of view of the virtual image (300) increases with an increase in the viewing distance (L0), which makes the observer of the virtual image (300) feel uncomfortable. However, the “constant” referred to here may not be strictly “constant”, and the display angle of view may be substantially constant within a predetermined range including some allowable error.

  With respect to the display system (1) according to the seventh aspect, in the sixth aspect, the adjustment unit (50) is configured to adjust the viewing distance (L0) so that the brightness of the virtual image (300) is within a predetermined target range. Accordingly, it is preferable to adjust the brightness of the virtual image (300). According to the seventh aspect, for example, the brightness of the virtual image (300) visible to the observer fluctuates when the size of the image (7) is changed in order to keep the display angle of view of the virtual image (300) constant. Can be suppressed.

  Regarding the display system (1) according to the eighth aspect, in any one of the first to seventh aspects, the projection unit (3) includes, as an optical element, a zoom lens (32) that transmits the output light. It is preferable to have. Moreover, it is preferable that the projection unit (3) can change the viewing distance (L0) by changing the position of the zoom lens (32). According to the eighth aspect, the viewing distance (L0) can be changed with a simple configuration.

  Regarding the display system (1) according to the ninth aspect, in any one of the first to eighth aspects, the image forming unit (2) includes a liquid crystal panel (21) whose front surface constitutes the display surface (210). And a light source device (22) serving as a backlight of the liquid crystal panel (21). According to the 9th aspect, even if it is a display system (1) which has a liquid crystal panel (21), the display quality and visibility fall of a virtual image (300) can be suppressed.

  The control device (10) according to the tenth aspect includes an adjustment unit (50) used in the display system (1) according to any one of the first to ninth aspects. According to the 10th aspect, the control apparatus (10) which can suppress the display quality and visibility fall of a virtual image (300) can be provided.

  The control method according to the eleventh aspect is a control method of the display system (1). The display system (1) includes an image forming unit (2, 2A) and a projection unit (3, 3A). The image forming unit (2, 2A) has display surfaces (210, 230), and forms an image (7) on the display surfaces (210, 230). The projection unit (3, 3A) projects a virtual image (300) corresponding to the image (7) onto the target space (400) by the output light of the image forming unit (2, 2A). The display system (1) is configured to be able to change the viewing distance (L0) from the eye box (800) to the virtual image (300). The control method includes an adjustment process for adjusting the brightness of the virtual image (300) according to the viewing distance (L0). According to the 11th aspect, the control method which can suppress the display quality and visibility fall of a virtual image (300) can be provided.

  A program according to a twelfth aspect causes a computer system to execute the control method of the display system (1) according to the eleventh aspect. According to the 12th aspect, the function which can suppress the display quality and visibility fall of a virtual image (300) can be provided.

  The mobile body (for example, automobile 100) according to the thirteenth aspect includes a display system (1) according to any one of the first to ninth aspects and a reflecting member that reflects light from the projection unit (3, 3A). (For example, windshield 101). According to the 13th aspect, the moving body which can suppress the display quality of a virtual image (300) and the fall of visibility can be provided.

DESCRIPTION OF SYMBOLS 1 Display system 2, 2A Image formation part 21 Liquid crystal panel 210, 230 Display surface 22 Light source device 3, 3A Projection part 32 Zoom lens 10 Control apparatus 50 Adjustment part 7 Image 100 Car (mobile body)
101 Windshield (reflective member)
300 Virtual image 400 Target space 800 Eyebox L0 Viewing distance

Claims (13)

An image forming unit that has a display surface and forms an image on the display surface; and a projection unit that projects a virtual image corresponding to the image onto a target space by output light of the image forming unit. The display system is configured to change the viewing distance from the eyebox to the virtual image,
An adjustment unit that adjusts the brightness of the virtual image according to the viewing distance;
Display system. The adjustment unit further adjusts the brightness of the virtual image according to ambient illuminance.
The display system according to claim 1. The adjustment unit adjusts the brightness of the virtual image by changing the luminance of the display surface.
The display system according to claim 1 or 2. The adjustment unit adjusts the brightness of the virtual image by changing the brightness of the content included in the image.
The display system of any one of Claims 1-3. The adjustment unit increases the brightness of the virtual image as the viewing distance increases.
The display system of any one of Claims 1-4. The display angle of view of the virtual image projected by the projection unit is constant even when the viewing distance changes.
The display system of any one of Claims 1-5. The adjustment unit adjusts the brightness of the virtual image according to the viewing distance so that the brightness of the virtual image falls within a predetermined target range.
The display system according to claim 6. The projection unit
As an optical element, it has a zoom lens that transmits the output light,
The viewing distance can be changed by changing the position of the zoom lens.
The display system of any one of Claims 1-7. The image forming unit includes:
A liquid crystal panel whose front surface constitutes the display surface;
A light source device serving as a backlight of the liquid crystal panel;
Having
The display system of any one of Claims 1-8. It is provided with the adjustment part used for the display system according to any one of claims 1 to 9.
Control device. A display system control method comprising: an image forming unit that has a display surface and forms an image on the display surface; and a projection unit that projects a virtual image corresponding to the image onto a target space by output light of the image forming unit. The display system is configured to change the viewing distance from the eyebox to the virtual image,
An adjustment process for adjusting the brightness of the virtual image according to the viewing distance;
Display system control method. A computer system is caused to execute the display system control method according to claim 11.
program. The display system according to any one of claims 1 to 9,
A reflection member that reflects light from the projection unit,
Moving body.

Images